3-tier Mode

I have a superficial understanding of the three layers. I have read the relevant materials over the past few days. I just want to talk about the summary and basic establishment of an additional small example! After reading it, I felt that it was similar, and my understanding didn't seem to have changed much, but it just deepened. But if you think about this for a few days, let's summarize it!

When you went to the restaurant for dinner, we met three layers. Let's have dinner!

The role of a waiter is to serve you food and collect your information, such as a shredded fish or a few bottles of beer or kebab! In short, all your requests are for the waiter! As for the men and women who are responsible for purchasing materials for the chefs, you do not need to know. All for the sake of customers is the purpose of the waiter! Wait for the waiter to resign or have something to do. Let's change the waiter. The whole process will not change much!

The following is the cook. The cook starts cooking according to his craft (logic) After receiving the information from the waiter. Contact the buyer when materials are required. After you finish the task, let the waiter go. The cook only cooks food, and the others do not care! This is the case for chefs!

The buyer prepares and updates the materials according to the requirements of the cook! His service object is material!

The relationship between the three is as follows: the waiter contacts the cook, and the cook does not need to contact the waiter. The cook contacts the buyer, and there is no need for the buyer to contact the cook. This is a bit awkward to hear, but this is the case. Although it is a bit difficult to talk about in life, but think about it, if the cook has prepared the food, it will be okay, and the purchaser will be able to manage the materials. It is easy to make mistakes because it is too time-consuming!

In addition, there is something called a data model. I think it encapsulates a set of methods, and each layer can call it, just like a menu in a restaurant, which can be used by waiters, chefs, and purchasers. Menus cannot be called by waiters, chefs, or purchasers.

The boss arranged it in this way. Think about who is responsible for the change. If you have a new market, you only need to add a buyer. The number of chefs and waiters remains unchanged. Speaking of security, if every cook purchases it in person, although the efficiency has improved, there are so many people in the market. If you put it with me, it's hard to say that you're here! If you come to a dedicated person, it's safe!

The three layers of thinking seem to have been studied in the future. Although they are different, their thoughts have not changed! With the development of social production, there are many such things around us! Computers are born from life. Of course, this is no exception!